The subject grant proposal is for the support of a Spanish speaking Summer School entitled "Practical Course in Radiation Therapy Dosimetry" to be held August 3-6, 1988 in San Antonio, Texas, immediately preceeding the annual meeting of the American Association of Physicists in Medicine which is being held concurrently with the World Congress of Medical Physics and Biomedical Engineering. Expected attendees will be primarily from Latin American countries, although some attendees from the United States, Spain, and other Spanish speaking countries are anticipated. Topics to be addressed include: dosimetry concepts, instrumentation, dosimetry standards, phantoms, dosimetry protocols for low, medium and high energy photons and electrons, intercomparison of protocols, and commissioning of radiotherapy equipment. This Course will provide practical training not ordinarily available to Central and South American medical physicists. The result of this training will be improved dosimetry and accuracy of dose delivered to cancer patients and the resultant improvement in health care in these under-developed countries. An added benefit might be that courses of this nature will encourage participants to become more responsive and active in cooperative clinical trials in radiation therapy.